In the field of power systems, it has been known to connect a rectifier to an alternating current (AC) power source to derive a direct current (DC) for motors or other loads. A rectifier connected to a 3-phase AC voltage source, however, generates undesired current harmonics, which can include at least the 5th, 7th, 11th, 13th, 17th, and 19th harmonics, which can introduce noise and other artifacts in the power circuit.
To address that undesirable harmonic content, it has been known to use a shunt active power filter.
Moreover, the application of a shunt active power filter to a variable frequency system has not been demonstrated. In a shunt active power filter designed to operate on source voltages which are variable, such as between 360-800 Hz, the range and amplitude of potential harmonics of the source current can be significant. Providing a way to selectively tune to, and dampen, those harmonics has not been established.
It may be desirable to provide methods and systems for tuning the control of a shunt active power filter over a variable frequency, in which harmonics generated at any point over a range of power source frequencies can be selectively tuned-for and dampened to prevent spurious output voltages to loads.